Reversible ink ribbon feed device having unitary bulk sensors

ABSTRACT

An ink ribbon feed device comprising a pair of spaced intermittently driven ratchet wheels for carrying a pair of ink ribbon reels, structure for selectively advancing one or the other of the ratchet wheels, a reciprocal lever pivotally connected at one end of the advancing structure and a spring biased ribbon detect lever coacting with the advancing structure for pivoting the advancing structure into engagement with one or the other of the ratchet wheels for thereby reversibly feeding ink ribbon from one reel to the other.

United States Patent 1191 Shimodaira Oct. 7, 1975 [54] REVERSIBLE INK RIBBON FEED DEVICE 1,937,145 11/1933 Gollwitzer 101 336 HAVING UNITARY BULK SENSORS E g" 272 enne ye a Inventor: Tadayoshl shlmodalra, MatsumQto, 2,335,679 11/1943 Kennedy 6:61 101/336 Japan 2,487,834 11/1949 Stolz 197/165 2,505,991 5/1950 Reinhold 197/162 [73] Assgnees? I P 2,691,342 10/1954 Johnston et a1 101/336 x Tolfyo; Shmsh" Salk Kabushlkl 2,972,402 2 1961 Howard 197/165 Kalsha, Suwa, both of Japan 3,037,448 6/1962 Blodgett et al. 101/336 3,513,957 5/1970 Ricciardi et a1. 197/151 [22] July 1973 3,542,183 11 1970 Stiffler 197/165 [211 App] 380,646 3,786,906 1/1974 Okabe 197 161 Primary ExaminerClifford D. Crowder [30] Forelgn Apphcatlon Pnonty Data Attorney, Agent, or Firm-Blum, Moscovitz, Friedman July 19, 1972 Japan 47-72223 & Kaplan Aug. 23, 1972 Japan 47-83639 [57] ABSTRACT An ink ribbon feed device comprising a pair of spaced [58] Fie'ld 60 161 162 intermittently driven ratchet wheels for carrying a pair 61 1 101/336 of ink ribbon reels, structure for selectively advancing 4 one or the other of the ratchet wheels, a reciprocal [56] References Cited lever pivotally connected at one end of the advancing structure and a sprmg biased r1bb0n detect lever 00- UNITED STATES PATENTS acting with the advancing structure for pivoting the 36,763 10/1862 Bailey l0l/336 UX advancing tructure into engagement one or the 715,456 12/1902 Burk 101/336 UX other of the ratchet wheels for thereby reversibly feed- 1 ing ink ribbon from one reel to the other. 10/1933 Dugdale lOl/336 7 Claims, 10 Drawing Figures US. Patent Oct. 7,1975 Sheet 1 of6 3,910,399

FIGII US. Patent 0m. 7,1975 Sheet 2 of6 3,910,399

US. Patent Oct. 7,1975 Sheet 3 of6 3,910,399

I US. Patent Oct. 7,1975 ShEet 5 of6 3,910,399

a 3 m F a m m w w w W \\K 2 n as 5 0 2 0 l I! I I E 1-! 6 US. Patent Oct. 7,1975 Sheet6 f6 3 ,910,399

REVERSIBLE INK RIBBON FEED DEVICE HAVING UNITARY BULK SENSORS BACKGROUND OF THE INVENTION This invention relates to a device for reversibly feeding ink ribbon through the print space provided in a compact printer or the like. More particularly, the present invention relates to an ink ribbon feed device provided with detecting means for detecting the outer diameter of reeled ink ribbon for selectively reversing ribbon feed from reel to reel.

Conventionally, compact printers and the like are provided with ribbon feed reversing mechanisms for alternately feeding an ink ribbon from one reel to another. Usually printing devices are provided with a pair of spaced ink ribbon reels which carry wrapped ends of an ink ribbon. To assure that a clear imprint occurs when a print hammer strikes the ribbon fed through the print space, the ribbon is fed from one reel to the other during the printing operation. To eliminate ribbon reel interchange, these printing devices are provided with ribbon feed reversing mechanisms for alternately reversing ribbon feed travel between the reels.

The prior art devices for reversing ribbon feed direction between reels usually coact with eyelets mounted at both ends of the ribbon or include members which apply tensile force to the ribbon or include a pair of detecting members for detecting the outer diameter of the reeled ribbon. All of these prior art devices are complex and delicate and in many cases mirror image components are employed for coacting with each ribbon reel. These prior art devices are therefore bulky and difficult to service and correspondingly increase the size and cost of any printer device in which they may be employed.

Accordingly, there is provided by this invention a ribbon feed reversing mechanism which is compact, easy to service and employs a minimum of moving parts.

SUMMARY OF THE INVENTION Generally speaking, in accordance with the invention, an ink ribbon feeder for a printer is provided which includes a pair of spaced, coplanar, rotatably mounted means for intermittently rotating a pair of ink ribbon reels, an ink ribbon reel rotatably mounted on each of said rotatably mounted means for linearly feeding an ink ribbon through a selected print path alternately from reel to reel, oscillatable means for selectively advancing one or the other of said rotatably mounted, spaced, coplanar means for advancing ink ribbon onto the advanced spool, a reciprocable lever pivotally connected at one end of said oscillatable means for driving said oscillatable means for thereby advancing one or the other of said rotatably mounted, spaced, coplanar means, and a spring biased ink ribbon detect lever for selectively oscillating said oscillatable means into engagement with one or the other of said rotatably mounted, spaced. coplanar means for advancing the ink ribbon reel rotatably mounted thereon.

The oscillatable means for selectively advancing the ink reels is provided with a pair of equispaced advancing pawls for advancing the rotatably mounted, spaced, coplanar means with which it is engaged. The oscillatable means is also provided with a pair of equispaced reversing pawls for coacting with the detect lever for thereby shifting the oscillatable means.

Accordingly, a unitary detect lever is provided for detecting the amount of ribbon on either spool and for reversing the ribbon feed direction from one spool to the other. In the past plural detect levers have been employed for accomplishing these functions.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWING For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawing, in which:

FIG. 1 is a plan view of one embodiment of the device of the invention;

FIG. la is a sectional view of the embodiment shown in FIG. 1 taken along line la la thereof;

FIG. 2 is a perspective view of a detect lever of the type employed in the embodiment shown in FIG. 1;

FIG. 3 is a plan view of another embodiment of the device of the invention;

FIG. 3a is a sectional view of the embodiment shown in FIG. 3 taken along line 3a 3a thereof;

FIG. 4 is a plan view of yet another embodiment of the device of the invention;

FIG. 4a is a sectional view of the embodiment shown in FIG. 4 taken along line 4a 4a thereof;

FIG. 5 is a perspective view of the detect lever employed in the embodiment shown in FIG. 4;

FIG. 6 is a plan view of still another embodiment of the device of the invention; and

FIG. 6a is a sectional view of the embodiment shown in FIG. 6 taken along line 6a 6a thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2, there is provided a pair of spaced, coplanar ratchet wheels 1 and 2 rotatably mounted respectively on rotary shafts 3 and 4 for intermittently rotating respective ribbon reels l7 and 17' (not shown) mounted thereon. Reel driving member 5 is symmetrically configured and is provided with a pair of equispaced reversing pawls 6 and 6' and a pair of equispaced feeding pawls 9 and 9'. Reel driving member 5 is pivotally mounted on driving lever 7 by shaft 8 and may be reciprocably driven thereby as shown by arrows A and B of FIG. 1. Reel driving member 5 is provided with feeding pawls 9 and 9 for. translating the lever actuated reciprocating motion thereof to intermittent rotation for ratchet wheel 1 or 2. A detect lever 11 is pivotally connected to base plate 15 of the device by a shaft 14. Detect lever 11 is provided with a pair of coplanar arms which terminate in respective fingers l2 and 12' arranged for respectively engaging reversing pawls 6 and 6' of reel driving member 5. An elbowed member of detect lever 11 is provided with edges 13 and 13 on an expanded neck portion for detecting the outer diameter of an ink ribbon (not shown) that may be wrapped on a reel 17 rotatably mounted on ratchet wheel 2. While not shown, an identical reel, 17 is rotatably mounted on ratchet wheel 1.

A free floating torsion coil spring 16 is connected at one end of a stud 10' mounted in a tail portion 10 of reel driving member 5. At its other end torsion coil spring 16 is connected to an interiorly extending stud 11' mounted on detect lever 11. Torsion coil spring 16 oppositely biases detect lever 11 and reel driving member 5 for biasing a ribbon sliding edge, for instance, 13 of detect lever 11 against the perimeter of ribbon wrapped on reel 17 and for biasing feeding pawl 9 of reel driving member 5 into engagement with teeth of ratchet wheel 1.

In the position shown in FIG. 1, the ribbon pick up direction is about to be reversed and there is shown ribbon being reeled onto the ink ribbon reel mounted on ratchet wheel 1 and being drawn from ribbon reel 17 mounted on ratchet wheel 2. Ratchet wheel 1 is intermittently rotated by feeding pawl 9 in the direction of arrow F in response to the A directional driving movement of driving lever 7 for reeling ink ribbon onto the ink ribbon reel rotatably connected to ratchet wheel 1 and displacing it from ink ribbon reel 17 mounted on ratchet wheel 2. During the reeling operation, the ribbon diameter on reel 17 is reduced whereby detect lever 11 gradually rotates in the direction of arrow E in response to the bias of torsion coil spring 16. The edge 13 of detect lever 11 constantly engages the periphery of the reel'ed ribbon during this phase of the operation.

As spring biased detect lever 11 gradually rotates in the direction E, finger 12 of detect lever 11 engages re ciprocating reversing pawl 6 of reel driving member 5 and driving lever 7 is reciprocably driven in the di-- rection of arrow B, reel driving member 5 pivots on shaft 8 in the direction of arrow C for engaging driving pawl 9' with ratchet wheel 2. Simultaneously therewith tail portion 10 of reel feeding member 5 is displaced in the direction of arrow D to the position shown in phantom line. while detect lever 11 is rotated oppositely from the direction of arrow D by the spring bias of torsion coil spring 16. As thus described, reel driving member 5 and detect lever 11 oppositely rotate for re \ersing the ribbon reeling direction from ratchet wheel 1 to ratchet wheel 2.

While the FIG. 1 embodiment is not shown as including a means for preventing ratchet backlash attributable to movement of reel driving member 5 in the direction of arrow B, any backlash that may occur can be prevented by applying a frictional brake between ratchet wheels 1 and 2 and respective shafts 3 and 4.

As best seen in FIG. 3, discrete reel driving members and reversing members may be provided. There is shown in FIG. 3 a feeding pawl lever provided with pawls 19 and 19 pivotally mounted on driving lever 37 by shaft 38. A reversing member 21 is provided with reversing pawls 36 and 36 and is also mounted on driving lever 37 by shaft 38. A stud 2.2 fixedly connects feeding pawl lever 20 and reversing member 21 for moving both members together.

A spring biased lever 23 is provided for preventing backlashing in ratchet wheels 1 and 2. Lever 23 pivots on stud 24 according to the oscillating action of feeding pawl lever 20 which in selected oscillating positions abuts a sidewall 23 of lever 23 and pivots lever 23 against the spring bias of torsion coil spring 25.

As shown in FIG. 3, reversing member 21 and driving lever 37 are mounted on the back of base plate 15, while feeding pawl lever 20 and lever 23 are mounted on the front of base plate 15. According to this particular embodiment ratchet wheels 1 and 2, feeding pawl lever 20 and lever 23 are arranged for providing a flat ribbon device.

The embodiment shown in FIG. 3 operates on the same principles and with the same detect lever 11 as described in connection with FIG. 1 and ribbon feed reverse is accomplished in the same way by interaction between fingers 12, 12 provided on arms of detect lever 1 1. Identical numbers refer to substantially identical parts in FIGS. 1 through 3.

In connection with the embodiment shown in FIGS.

4 and 6 a detect lever 115 as shown in FIG. 5 is employed. Detect lever 115 is substantially identical with the detect lever embodiment shown in FIG. 2 however the parts thereof have been renumbered to conform with numbering for the embodiments of FIGS. 4 and 6. In the embodiments of FIGS. 4 and 6 identical numbers refer to substantially identical elements. The principle of operation of these embodiments is substantially the same as that described in connection with the embodiment shown in FIG. 1, however, in each of the embodiments of FIGS. 4 and 6 interacting discrete members advance the ratchet wheels and coact with the detect lever for reversing the ribbon feed direction in the manner described in connection with FIG. 3. Referring now to FIG. 4, there is provided a pair of ratchet wheels 101 and 102 which intermittently rotate a corresponding pair of ink ribbon reels, only one of which is shown as 1 17. Axial central shafts 103 and 104 of ratchet wheels 101 and 102 serve to rotatably mount the ink ribbon reels thereon. An ink ribbon reel driving member 105 is provided with a pair of equispaced reversing pawls 106 and 106 for interacting respectively with fingers 116 and 116 for thereby reversing the ribbon feed direction. Ink ribbon reel driving member 105 is pivotally mounted on a driving lever 107 by a shaft 108 and is reciprocated thereby as shown by directional arrows A and B. Ink ribbon reel driving member 105 is provided with a pair of equispaced feeding pawls 109 and 109' for translating the reciprocating motion thereof to intermittent rotation of ratchet wheels 101 or 102. A torsion coil spring 110 is connected at one end to ink ribbon reel driving member 105 and at the other end thereof to driving lever 107. A reel feed reversing member 111 pivotally connected to base plate 120 by shaft 113 is provided with a trapezoidally configured aperture 112 for receiving a pin 114 fixedly connected to driving member 105. Pin 114 engages a sidewall 112 of aperture 112 for transmitting the motion of member 105 to member 111 as shown by directional arrow C.

Detect lever 115 is provided with fingers 116 and 116 in one plane and in a second plane with ink ribbon sliding edges 118 and 118. Edges 118 and 118 are alternately spring biased against the periphery of ink ribbon wrapped on a reel 117. Detect lever 115 is rotatably mounted on base plate 120 by shaft 119. Torsion coil spring 121 connected at both ends. respectively to detect lever 115 and member 111 for oppositely biasing detect lever 115 and member 111 is free floating and it provides a biasing force whereby detect lever In FIG. 4, there is shown a critical moment when the reeling direction of the ribbon (not shown) is about to be reversed while ribbon is being reeled onto a reel (not shown) carried by ratchet wheel 101 from the reel 117 carried on ratchet wheel 102. Ratchet wheel 101 is intermittently rotated in the direction of arrow D in response to the motion of driving lever 107 in the A direction for reeling up ink ribbon onto the ribbon wheel located thereon. As ribbon is fed from reel 117 to the reel located on ratchet wheel 101 the ribbon diameter thereof decreases and accordingly detect lever 115 engaged with the ribbon diameter along edge 118 rotates gradually in the direction of arrow F in response to the spring bias of torsion coil spring 121. As detect lever 115 gradually rotates in the direction shown by arrow F in response to the bias of torsion coil spring 121 finger 116 thereof intrudes into the path of reversing pawl 106 of ink ribbon reel driving member 105 and as driving lever 107 moves in the direction of arrow B member 105 reverses as directionally shown by arrow C for thereby engaging feeding pawl 109 thereof with ratchet wheel 102. Pin 114 of member 105 reverses member 111 directionally shown by an arrow E and detect lever 115 is oppositely rotated from the direction shown by arrow E in response to the bias of torsion coil spring 121. As thus shown member 105 is reversed for thereby reversing detect lever 115 through member 111 for reeling up ink ribbon on reel 117 located on ratchet wheel 102.

While there is not shown in the embodiment of FIG. 4 a means for preventing backlashing of ratchet wheels 101 and 102 due to the action of member 105 in the direction of arrow B, backlash may be prevented by applying frictional brakes between ratchet wheel 101 and shaft 103 and ratchet wheel 102 and shaft 104.

Referring now to FIG. 6, where there is shown yet another embodiment of the invention, a member 130 is pivotally connected to driving lever 107' by shaft 108' and is provided with pawls 136 and 136, feeding pawls 139 and 139 and a reversion transmitting portion 131. A second member 132 is rotatably mounted on base plate 120 by shaft 113 and is provided with a pair of pawls 133 and 133 for preventing backlashing of respective ratchet wheels 101 and 102. Either of pawls 133 or 133 is engaged, respectively, with either of ratchet wheels 101 or 102 by torsion coil spring 121' for preventing backlashing therein. When member 130 is reversed in the direction of arrow C, reversion transmitting portion 131 of member 130 engages backlash preventing pawl 133 for reversing member 132 in the direction of arrow E. As member 132 is directionally reversed, detect lever 115 reverses oppositely thereto in response to the bias of torsion coil spring 121 for thereby completing the reversing operation. The embodiment shown in FIG. 6 is a preferred embodiment because of the inclusion therein of a means for preventing backlash in ratchet wheels 101 and 102.

It may therefore be observed that devices of this invention are precision operated, employ a single ribbon reel detect lever and are of compact construction. Either a single means may be employed for reversing ribbon feed between ink ribbon reels or plural coacting means may be employed for that purpose.

It will thus be seen that the objects and advantages set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall there between.

What is claimed is:

1. An ink ribbon feeder for a printer comprising a base, a pair of spaced, coplanar means rotatably mounted on said base for intermittently rotating a pair of ink ribbon reels, oscillatable means alternately coacting with each of said pair of rotatably mounted spaced, coplanar means for selectively intermittently advancing one or the other of said rotatably mounted, spaced coplanar means, reciprocable means pivotally connected to said oscillatable means for reciprocating said oscillatable means for thereby intermittently advancing one of said rotatably mounted, spaced, coplanar means, a pivotally mounted detect lever for sensing a predetermined unreeled quantity of ink ribbon on an ink ribbon reel and for shifting said oscillatable means into position for intermittently rotating said other of said rotatably mounted, spaced, coplanar means, said detect lever including an elbowed member having an expanded neck portion provided with ink ribbon sliding surfaces, and means for oppositely biasing said ink ribbon detect lever and said oscillatable means, said detect lever including a pair of coplanar branched arms, each arm terminating in a finger for engaging opposite sides of said oscillatable means for thereby shifting said oscillatable means into engagement with one or the other of said pair of rotatably mounted spaced, coplanar means.

2. The ink ribbon feeder of claim 1 wherein said oscillatable means includes first and second coacting members, said first member being cooperable with one of said pair of rotatably mounted spaced, coplanar means for intermittently rotating said rotatably mounted, spaced, coplanar means, said second member being cooperable with said detect lever for shifting said first member into position for intermittently rotating said other of said rotatably mounted spaced, coplanar means.

3. The ink ribbon feeder of claim 1 including an ink ribbon reel mounted on each of said pair of rotatably mounted spaced, coplanar means for intermittent rotation therewith.

4. The ink ribbon feeder of claim 1 wherein each of said pair of rotatably mounted spaced, coplanar means is a ratchet wheel.

5. The ink ribbon feeder of claim 4 wherein said oscillatable means includes an equispaced pair of advancing pawls for advancing one or the other of said ratchet wheels.

6. The ink ribbon feeder of claim 1 wherein said oscillatable means includes an equispaced pair of position reversing pawls engageable with one or the other of said branched arm detect lever fingers.

7. The ink ribbon feeder of claim 1 including backlash preventing means coacting with said oscillatable means and cooperable with one or the other of said pair of rotatably mounted spaced, coplanar means. 

1. An ink ribbon feeder for a printer comprising a base, a pair of spaced, coplanar means rotatably mounted on said base for intermittently rotating a pair of ink ribbon reels, oscillatable means alternately coacting with each of said pair of rotatably mounted spaced, coplanar means for selectively intermittently advancing one or the other of said rotatably mounted, spaced coplanar means, reciprocable means pivotally connected to said oscillatable means for reciprocating said oscillatable means for thereby intermittently advancing one of said rotatably mounted, spaced, copLanar means, a pivotally mounted detect lever for sensing a predetermined unreeled quantity of ink ribbon on an ink ribbon reel and for shifting said oscillatable means into position for intermittently rotating said other of said rotatably mounted, spaced, coplanar means, said detect lever including an elbowed member having an expanded neck portion provided with ink ribbon sliding surfaces, and means for oppositely biasing said ink ribbon detect lever and said oscillatable means, said detect lever including a pair of coplanar branched arms, each arm terminating in a finger for engaging opposite sides of said oscillatable means for thereby shifting said oscillatable means into engagement with one or the other of said pair of rotatably mounted spaced, coplanar means.
 2. The ink ribbon feeder of claim 1 wherein said oscillatable means includes first and second coacting members, said first member being cooperable with one of said pair of rotatably mounted spaced, coplanar means for intermittently rotating said rotatably mounted, spaced, coplanar means, said second member being cooperable with said detect lever for shifting said first member into position for intermittently rotating said other of said rotatably mounted spaced, coplanar means.
 3. The ink ribbon feeder of claim 1 including an ink ribbon reel mounted on each of said pair of rotatably mounted spaced, coplanar means for intermittent rotation therewith.
 4. The ink ribbon feeder of claim 1 wherein each of said pair of rotatably mounted spaced, coplanar means is a ratchet wheel.
 5. The ink ribbon feeder of claim 4 wherein said oscillatable means includes an equispaced pair of advancing pawls for advancing one or the other of said ratchet wheels.
 6. The ink ribbon feeder of claim 1 wherein said oscillatable means includes an equispaced pair of position reversing pawls engageable with one or the other of said branched arm detect lever fingers.
 7. The ink ribbon feeder of claim 1 including backlash preventing means coacting with said oscillatable means and cooperable with one or the other of said pair of rotatably mounted spaced, coplanar means. 